Opeyemi Joshua

Assessment of the Quality Steel Reinforcement Bars Available in Nigerian Market

The use of substandard and steel reinforcement rods in the construction of structural steel concrete elements of a building, most especially in floor slabs, has been identified as one of the most important causes of structural failures in buildings in Nigeria. This research investigated the mechanical properties (yield strength, ductility and the ultimate tensile strength) of 12-mm diameter steel bars commonly used in reinforcing floor slabs using an extensometer. Results obtained from the tests showed that only three (3) brands out of a total of nine (9) tested most commonly used brands of sampled rods showed yield strengths greater than 460N/mm2. The yield strengths obtained range between 337.72 N/mm2 and 569.71 N/mm2. The study confirmed that the wide usage of substandard steel reinforcement bars in the Nigerian market is a major contributing factor to increasing incidences of structural building failures in the country when viewed from the angle of variability in material quality.

Data on factors influencing the cost, time performance of the Industrialized Building System

The data article provides the factors that influence the cost; time performance of the Industrialized Building System (IBS), its prospects and challenges. A survey technique was used for this research. Structured Questionnaires were administered to occupants of prefabricated buildings and interviews were conducted with the professionals in the building industry. Statistical Package for Social Sciences (SPSS version20) was used to analyse the data obtained from the questionnaires. The variables were ranked based on Relative Importance Index (RII) calculation. The Data indicated that IBS would be more economical if used for mass production.

Data on the pozzolanic activity in coconut shell ash (CSA) for use in sustainable construction

The data presented herein are results of the research summary of the investigation for pozzolanic activity in coconut shell ash (CSA) towards a sustainable construction. The data article provides information on the properties of Coconut Shell Ash that are indicative of pozzolanic activity as stated in ASTM C618-15 (2015) [1], BS EN 197-1 (2011) [2] and Joshua et al. (2018) [3]. The data are the physical property of the sand used in determining the binder strengths and the chemical and physical properties (oxide composition and Strength Activity Indices respectively) of the pulverized, calcined and sieved Coconut Shell Ash.

Data of the properties of rebar steel brands in Lagos, Nigerian market used in reinforced concrete applications

The data presented herein are compilations of the research summary of “Assessment of the Quality of Steel Reinforcement Bars Available in Nigerian Market” (Joshua et al., 2013) [1]. This data article provides information on the properties and cost of steel rebars used in reinforced concrete in Lagos, Nigeria. The data is based on the properties of 12 mm rebar brands which are the most used steel diameter in construction and they include actual diameters, yield strengths, ultimate strengths, ultimate/yield strength ratio, ductility and the cost of each brand. This data also contains the limiting standard properties of the highlighted properties in this data.

Experimental datasets on properties of river sand as an aggregate in replacement of crushed rock for interlocking stones production

The data explored the assessment of the quality of river sand as an aggregate in replacement of crushed stones which are widely used by majority of manufacturers in production of interlocking stones. Experimental tests carried out on river sand and crushed rock as aggregates include: Grain size distribution, Specific gravity, moisture content determination and Bulk density to determine the quality behavior parameters and (compressive strength) to determine the strength parameters. The data of the experiments are presented in Tables and Bar charts.

Survey dataset on professional's perception on site supervision and project performance

Effective site supervision plays an important role in construction project delivery. This situates site supervisors in taking the responsibilities of coordinating and controlling all physical aspects of the day-to-day task in construction projects. A cross-sectional design approach was adopted by administering a well-structured questionnaire to selected built environment professionals. Descriptive statistics was performed on the data obtained and are presented on figures and tables. The data was also subjected to inferential statistics using Kruskal Wallis test to analyze the perceptions of respondents on effects of site supervision of construction works on completion time and quality respectively. The significance of the analyzed data is on identifying the effects of site supervision on project completion time and quality delivery. The analyzed data will also guide project stakeholders in selecting competent personnel in executing construction projects.

Data on mixing and curing methods effects on the compressive strength of concrete

Curing, though important is sometimes underrated in concrete production. This dataset provided shows the effects of four (4) different methods of curing on two distinct mix ratios. The data provided in this article are for a study that was conducted on one hundred and sixty (160) cube samples of mix ratios 1:2:4 and 1:1.5:3 while employing four (4) different methods of curing. The data given in the article displays the finding of the study. The findings can aid in prediction and optimization of concrete behavior and compressive strength when any of the curing methods are utilized.

Assessment of the Linkages and Leakages in a Cloud-Based Computing Collaboration among Construction Stakeholders

The uniqueness of the construction industry can be understood in the large volumes of information in terms of paper works, processes, and communication disseminated daily. The voluminous information requires close coordination which cloud based systems offer. The aim of this research is to assess the linkages and leakages in a cloud-based computing collaboration among construction stakeholders. A purposive sampling technique was used in selecting the participants of the study. A questionnaire based instrument was distributed to eighty (80) construction stakeholder in Lagos State, Nigeria. The data collected was analyzed using SPSS v.21. Statistical tools such as frequencies, stacked bars, mean scores, factor analysis, and analysis of variance (ANOVA) were used in the study. The result of the study revealed that construction stakeholders rarely utilize cloud-based technologies for their construction processes. Construction professionals that access cloud based technologies, do so with their smart mobile phones, laptops, and tablet. The study classified the leakages that exist in the use of cloud-based technologies as securitybased factors, cloud-based infrastructure factors, and cloud-based benefits deficiency based factors. In conclusion, the study revealed that the linkages in the use of cloudbased technologies include knowledge sharing, remote access of back-office activities and engendering collaboration among construction stakeholders. It was recommended that construction stakeholders should leverage on the benefits cloud-based technologies has to offer in today’s competitive economy. Construction stakeholdersshould be adequately informed on the available cloud-based computing technologies and the additions it can bring into the construction process. Cloud computing technology vendors should improve on the security and privacy features of the platform for adequate protection of building data.

Cost Management Practice of Construction Firms and Its Influencing Factors: Lessons from Southwestern Nigeria

The growing need at maintaining steady cost projection of construction projects has been an issue of serious concern to both the clients and the construction practitioners on sites. Also, cost deviation from initial cost plan and cost budget has been prevalent on construction sites and no concerted efforts have been made at addressing this phenomenon. This study therefore examined the factors that are considered to be affecting the cost management practice of construction firms in the southwestern Nigeria and also proffered possible ways of ameliorating the factors. Using survey approach, one hundred copies each of structured questionnaires were distributed to clients, contractors and consultants on construction sites in the study area while 72, 77 and 78 copies were duly filled and returned by the respondents respectively. Relative Importance Index (RII) technique was used for the analysis. The results revealed that poor leadership and in appropriate management, inefficient deployment of resources, excessive wastage of materials on sites, complex payment mechanisms, theft of materials on sites and variation during construction works are the prevailing factors affecting construction cost management practice in the study area. It was concluded that extra focus should be placed on the identified factors with a view to reducing cost of construction, enhancing construction performance and building confidence within the construction industry in the study area.

A Framework for Enhancing Contractor-Subcontractor Relationships in Construction Projects in Nigeria

The delivery capability of main contractors depends largely on the quality of their subcontractors and the harmonious relationships that exist between them. Research work was therefore conducted to identify the mechanisms to facilitate the understanding between these pairs and also develop a model that puts emphasis on the factors. To achieve this aim, one hundred questionnaires each were administered randomly to main contractors and labor-only subcontractors in the study area. Seventy-five and eighty-eight questionnaires were respectively filled and returned in this regard. The application of total weight value and rating index techniques shows that type of contract, scope of contract, payment terms, cooperative attitudes, third-party involvement are the main factors that influence this relationship and this was further validated by a model. The paper concludes that this methodology could culminate into a useful decision making tool for both main contractors and subcontractors during the development and execution stages of construction projects in the study area.